Choosing a power source for the N8102 & N8105 LED Power Distribution Boards

N8012 LED Power Distribution Board

Remember that when LEDs are in series, you add the device voltages together
and the power supply needs to provide at least that much voltage. Side-A
of the board uses current sources so resistors are not required to protect the
LEDs. However, the current sources take about 5 volts from the supply for power
leaving the remainder for the LED series to use. For example, if a
12-volt power
supply is used, each group on side-A will have 7 volts at its disposal
for calculation purposes. This means that if you want to have white (3.3-volt)
LEDs in a series group, you will be limited to 2 LEDs in the group (or a total
of 8 on side-A). If on the other hand you want red LEDs in the series
group (1.85-2 volt), you could have 3 LEDs in the group. Now, all of this is
based on a 12-volt supply. With a 18-volt DC supply, the number of LEDs in a
white LED group could be 4, filling up all available spots.

Side-B requires all LEDs have resistors selected based on what supply
voltage will be used.

Side-B will also support connection of filament type incandescent bulbs.
Be sure that the appropriate resistor is chosen based on the bulbs current and
voltage specifications.

Here’s a quick rule of thumb: With a 9-volt power source, a single board will
support 4 white LEDs on side A and 12 on side B for a total of 16. A
12-volt supply raises the total to 20 and an 18-volt supply would raise
it to 28.

As you might expect, we carry 12-volt and 18-volt power supplies.
These are highly-regulated precision switching power supplies that are small but
very powerful, and are quite inexpensive. They can be found below our
Distribution Board on the Lighting Accessories page.

Finally, remember to watch your resistor calculations carefully for side-B
as they relate to your DC voltage source. The higher the DC source voltage, the
greater the Power (wattage) size your resistors need to be. Always select
resistors that exceed the calculated milliwatt usage. A link to our
calculators page can be found here.

N8015 LED Power Distribution Jr.

Just like its bigger brother above, the N8105 has a current source side (top,
where current source chip is mounted) and a side that requires resistors for
connected LEDs (bottom side of board, shows the N8105 part number).

The current source side is configured for up to 4 series-wired LEDs and the
same rules and calculations apply that are shown for the N8102 above.
For example, if a 12-volt power supply is used, the current source side will
have 7 volts at its disposal for calculation purposes. This means that if you
want to have white (3.3-volt) LEDs in a series group, you will be limited to 2
LEDs in the group. If on the other hand you want red LEDs in the series
group (1.85-2 volt), you could have 3 LEDs in the group. Now, all of this is
based on a 12-volt supply. With a 18-volt DC supply, the number of LEDs in a
white LED group could be 4, filling up all available spots.

The bottom side will allow for up to 4 LEDs connected either as a series
group, individual LED with the own resistors (parallel configuration), or a
combination of series and parallel LEDs. This provides maximum flexibility to
support most wiring schemes.

The bottom side
will also support connection of filament type incandescent bulbs.
Be sure that the appropriate resistor is chosen based on the bulbs current and
voltage specifications.

Finally, remember to watch your resistor calculations carefully
as they relate to your DC voltage source. The higher the DC source voltage, the
greater the Power (wattage) size your resistors need to be. Always select
resistors that exceed the calculated milliwatt usage. A link to our
calculators page can be found here.